When you're browsing the web, do you keep an eye on the address bar at the top of your browser window?

It's the text bar that displays the address of the page you're currently viewing. You can type directly into it, if you like, but most of the time it's there for information's sake.

The addresses that appear there are technically called "URLs", which stands for Uniform Resource Locators, and you've probably noticed that some URLs make more sense than others.

Say you're browsing an online shop. If you see "shopname.com/products/dog-food/" in the address bar, you can make a pretty good guess about the contents of the page you've downloaded. It's going to be a page that sells dog food.

Sadly not all websites are made that way. A lot of them, especially online shops, end up with incredibly long URLs full of code numbers, meaningless strings of text, and random bits of data. The result is messy, cluttered URLs that don't make any sense to ordinary people.

There are two opposing views about this. Some people say that it doesn't matter what ordinary people think - the URLs are there mainly for the computer's benefit, not for a person's. As long as the computer can display the correct web page, it shouldn't matter what the URL looks like.

Mike Schinkel, on the other hand, cares a great deal about URLs. He is campaigning for "clean" URLs that make sense both to people and computers. His website, at www.welldesignedurls.org is full of advice and comment about the good way to present a web address to people.

It's worth getting to know the basics of reading URLs, because it can make your life easier when you're browsing. On some of the more confusing websites, where obvious links from one page to another are not easy to find, or simply don't take you to where you want to go, you might consider trying the art of "URL hacking".

This means simply deleting chunks of the URL in the hope that your edited version might take you somewhere interesting.

A well-made website should behave as expected. And the worst that can happen is you'll reach a "Page not found" error - and even that might include a search box, or a site map, to help you.

The BBC and Yahoo! jointly hosted an event called Hack Day in London a week or so ago. Several hundred geeks filled Alexandra Palace for a weekend of hacking, smushing, coding, eating, and playing Faceball.

The aim? Just to get some smart people together to do some creative thinking. If you want to know what they got up to, take a look at the links on www.hackday.org

At another geek get-together on the other side of the Atlantic, Apple hosted this years developers' conference.

Opening the event, Apple boss Steve Jobs upset a lot of the assembled Mac programmers by saying they'd have only be able to make software for the company's shiny new iPhone if they made it as a web application.

In other words, they're not allowed to mess with the inner workings of the phone itself, only to make stuff that works inside the phone's browser.

Some of the Apple faithful are not impressed: web apps are fine, they say, but only when you can access to the web.

* Giles Turnbull has a website at www.gilest.org